Micrometric compass



Jan. 21, 1936.

w. DANKHOFF MICROMETRIC COMPASS Filed March 15 1934 2 Sheets-Sheet-lInvenlor Mun/v DQNKHOZT DECEQSED.

Jan. 21, 1936. w DANKH FF 2,028,147

MICROMETBIC COMPAS S Filed March 13,. 1954 2 Sheets-Sheet l2 InventorMLMM DAN/(HOPE Dzcmszzp. L/Iu/Pa C. Z'TPEY. flaw/w mp rqz.

UNITED STATES BIICROMETEIC COMPASS William Dankhoff, deceased, late ofFalls Creek,

Pa., by Laurel C. Frey, administrator, Grafton,

W. Va.

Application March 13, 1934, Serial No. 715,369

Claims.

This invention relates to an improved micrometric instrument and hasmore particular reference to a novel measuring and adjusting gauge forsuch instruments as calipers, dividers and compasses. I

The invention as depicted in the accompanying drawings comprises a gaugeequipped compass, it beingunderstood that the same fundamentalstructural arrangement is susceptible for use in the construction of anequivalent instrument, such as a caliper, divider and the like.

Where accuracy and precision is required in tools and instruments ofthis classification, de-

pendable and efficient means must be provided for moving the legs of theinstrument toward and from each other in a minute manner, and at thesame time to definitely and legibly indicate the distance between thepoints of said legs. The inventor of the invention herein havingdiscovered the need 'for an arrangement of this type, evolved andproduced a unique structural assemblage characterized by featurescarefully selected and mechanically co-ordinated to accomplish thedesired results in a practicable and satisfactory manner.

ure 1 in the direction from left to right.

Figure 3 is a sectional view taken approximately on the plane of theline 3-3 of Figure 2.

Figure 4 is a detail horizontal sectional and elevational view takenapproximately on the plane of the line 4-4 of Figure 1.

Figure 5 is a perspective view of a self-adjusting anchoring andsupporting ring or annulus.

Figure 6 is a detail elevational view of the feednut.

In the drawings, in Figure 1 for example, it will be observed that theinstrument, known as a pair of dividers, is distinguished by thenumeral 1. This is of more or less conventional form in that it embodiesa pair of legs 8 and 9 pivotally connected together at their upper orconverging ends, as indicated at I0. At opposed points and adjacent thepivot, the legs are formed with ringlike enlargements I l and 12 adaptedfor registration and designed to accommodate the adjusting, measuringand indicating means. This means is composed of a number of carefullyselected and mechanically co-ordinated parts.

Attention is first called to the numeral [3 which designates a hollowcylindrical adjusting and measuring screw. This is merely formed with 'aspiral groove l4 and provided at one end with a fixed, knurled head orfinger grip [5. The opposite end is internally screw threaded, asindicated in Figure 3, toaccommodate the threaded stem or shank N3 of adetachable, knurled cap I'I. Adjacent the cap, the adjusting screw isfashioned for swivel mounting in a self-adjusting oscillatory annulus orring it. This ring is made tovfit swingably in the supporting annulusl2. To this end, said annulus i2 is provided at diametrically oppositepoints with bearing holes to accommodate diametrically opposed trunnionsor pintles i9 carried by said ring. The right hand end of the feed screwis mounted for swivelling in this ring :3 and the ring is in turnmounted for oscillation in the annulus E2. The cap i1 is removable topermit the parts to be assembled and disassembled. Incidentally, thefeed screw is made hollow to render it light in weight. More over, thethreads, that is, the portions between the'grooves, are provided withcalibrations or graduations 20 which serve in a manner to be hereinafterdescribed.

Attention is called at this time to the numeral 21 which designates whatmay be conveniently described as a feed nut. This is provided withdiametrically opposite trunnions 22 mounted for oscillation in bearingholes formed in the annulus ll. Moreover, the nut is fashioned orthreaded for adjusting cooperation with the groove M of the feed screw,as detailed in Figure 4. Then too, it is provided with a pointer orindex 23 for cooperation with the graduations or calibrations 20, asshown in the assembled view in Figure l.

The gist of the invention is in the provision of a double leggedinstrument 1 wherein the legs are pivotally attached at one end andprovided intermediate their ends with opposed annular enlargements. Theenlargement 12 serves to accommodate a self-levelling or adjusting ringI8 which is mounted for swivelling therein. The enlargement I I servesto accommodate a correspondingly mounted or swingable feed nut carryingan index or pointer 23. This permits one end portion of the feed screwl3 to be swivelly mountr ed in the ring I 8, the intermediate oropposite end portion of said screw extending adjustably through said nut2|. Thus in a sense, we have a calibrated adjusting screw which servesas a gauge and which is operatively connected with the legs 8 and 9 toadjust said legs toward and from each other in a desired manner. Throughthe instrumentality of the pointer 23 cooperating with the graduations20, it is thus possible to determine the distance between the pointedends of said legs 8 and 9.

An arrangement of this type is adaptable, as before indicated, todifferent types of instruments, such as dividers, compasses, calipersand the like. It is, in a sense, an adjusting and indicating micrometer.It makes for accurate and dependable adjustment and measurment. In COD?trast to known types of instruments, it appears to be a uniqueadaptation whose features of construction transcend those of similararrangements.

It is thought that the description, taken in connection with thedrawings, will enable a clear understanding of the invention to be had.Therefore, a more lengthy description is thought unnecessary.

While the preferred embodiment of the invention has been shown anddescribed, it is to be understood that minor changes coming within thefield of invention claimed may be resorted to if desired.

It is claimed:

1. A structure of the class described comprising an instrument embodyinga pair of legs one of which is adjustable toward and from the other, afeed'nut carried by one of said legs, an adjusting screw operativelyconnected with said feed nut, a swivel connection between one end .ofsaid screw and the remaining leg, said nut being provided with anindicating pointer, and said feed screw being provided with graduationswith which said pointer is co-operable.

2. A device of theclass described comprising an instrument including apair of legs one of which is adjustable toward and from the other, ananchoring ring pivotally mounted on one of said legs, a feed nutpivotally mounted on the opposite leg in alignment with said ring, afeed screw adjustably connected with said nut and 'swivelly connectedwith said ring, said nut being provided with an indicating pointer, andsaid feed screw being provided with calibrations with which said pointeris co-operable.

3. A structure of the class described comprising an instrument includinga pair of legs one of which is adjustable toward and from the other, theintermediate portions of said legs being provided with opposed annularportions, a ring mounted for oscillation in one of said annularportions, an adjusting nut mounted for oscillation in the remainingannular portions, said adjusting nut being provided with a pointer, afeed screw connected with said nut intermediate its ends and swivellyconnected at one end with said ring, said feed screw having its surfacegraduated for cooperation with said pointer.

' 4. A structure of the class described comprising an instrumentembodying a pair of duplicate legs one of which is movable toward andfrom the other, an anchoring and swivelling ring mounted for oscillationon one of the legs, a nut mounted for oscillation on the remaining legopposite said ring, said nut being provided with an indicating pointer,a hollow tubular feed screw formed at one end with a knurled fingergrip, the opposite end being internally screw threaded, a screw capconnected with said last named end, said last named end being swivellyattached to said ring and the intermediate portion being attached tosaid nut, said feed screw being graduated for cooperation with saidpointer.

5. A device of the class described, comprising a pair of legs one ofwhich is adjustable toward and from the other, a feed nut carried by oneof said legs, an adjusting screw operatively con nected with said feednut, a swivel connecting element between one end of said screw and theremaining leg, said feed screw being provided with graduations, and saidnut being provided with a pointer cooperable with said graduations.

LAUREL C. FREY, Administrator of the Personal Estate of WilliamDankhofi, Deceased.

